If you know the connection works with a cable directly from your laptop to what you’re connecting to, but it doesn’t work when going through your dock, it’s likely that your dock needs the power reset. To do so, remove the power cable in your dock and hold down the small button on the top of it for around 10 seconds, and then reconnect the power cable.
It is very important to note that you need to unplug the dock from your laptop before you do this as it can shut your laptop down as well if you reset the dock while the laptop is still plugged in!